This invention has particular application to interocclusal appliances, commonly referred to as splints, for bruxism and temporomandibular joint dysfunction syndrome. However, its utility is not limited to those particular problems.
U.S. Pat. No. 5,646,216, Watson, Jones and Moore, issued Jul. 8, 1997, describes such splints and methods and materials for making them. The disclosures of that patent are incorporated herein by reference.
The present invention is an improvement on the appliances and methods described in the patent, in that in the appliance of this invention, a hard shell covers the exterior occlusal, buccal and lingual surfaces of a relatively soft liner, and covers an outside undercut edge of the liner so as mechanically to join the liner and the shell, but to permit the teeth of the user to engage the soft liner. In the preferred embodiment, the shell and liner are fused at their mutual outer edges by the heat of a bur used in finishing the appliance. The advantages of the appliance of the present invention are, among others, that the joining of the shell and liner are not dependent upon chemical bonding, which in the case of some shell and liner materials is not entirely satisfactory, that the liner can be and is made very thin, to permit the use of a relatively thick shell, which makes for a durable appliance and maintains the integrity of the liner, which is formed initially to fit the teeth of a particular patient.